1. Field of the Invention
The present invention relates to a camera module having an anti-shake mechanism. More particularly, the present invention relates to a camera module having an anti-shake mechanism, in which an angle sensor can be positioned stably and a camera can have a sufficiently reduced size.
2. Description Related to the Prior Art
Portable electronic equipment, for example, a mobile telephone or portable information terminal device, having a function of a camera is widely used. A camera module for this purpose is a unit including lens optics and an image sensor, and incorporated in the portable electronic equipment in a suitable position.
For the purpose of obtaining high portability of the camera module, reduction of the weight and size of the camera module is generally more important than for a compact camera. Also, a high number of pixels in the image sensor and high resolution of the lens optics are important factors in order to form an image of a high image quality. Furthermore, there are known type of the camera module having an auto focus device (AF device) and/or an anti-shake device. The auto focus device automatically adjusts focus in order to obtain an image sharply even with simple manipulation. The anti-shake device functions to remove influence of a camera shake in the manual operation of a user's hands.
For the structure with the auto focus device and/or the anti-shake device, various components are required, including an auto focus mechanism (AF mechanism) and/or anti-shake mechanism, an angle sensor, controller, driver, and a flexible wiring board. The auto focus mechanism and/or the anti-shake mechanism moves the entirety or part of the lens optics. The angle sensor detects a camera shake. The controller and driver cooperate for driving an actuator in the auto focus mechanism or the anti-shake mechanism. The flexible wiring board interconnects those circuits and the angle sensor. However, there arises a problem of enlarging the size of the camera module due to an increase in the number of the components.
U.S. Pat. No. 8,406,617 (corresponding to JP-A 2010-250045) discloses the camera module having a digital imager or camera (module main body), a front cover and the flexible wiring board, in a form with a reduced size. The digital imager is in a block shape. The front cover covers a front side of the digital imager. Two bend portions are formed with the flexible wiring board in an L-shape. A gyrosensor (angle sensor) for an X direction and a driver IC are mounted on a first one of the bend portions. The gyrosensor for a Y direction and a control IC are mounted on a second one of the bend portions. The bend portions are directed in parallel with an optical axis direction of the lens optics. The gyrosensors, the driver IC and the control IC are arranged in spaces between the digital imager and the front cover.
In U.S. Pat. No. 8,406,617, the bend portions are disposed in the space between the digital imager and the front cover. Tilt or shift of the bend portions is likely to occur incidentally. The gyrosensors is also tilted, so that the axis of the gyrosensors cannot be kept in parallel with the optical axis direction. Precision in the shake correction will be low, as detection of an amount of the camera shake may be incorrect. There is no known type of the camera module in which the angle sensor is positioned stably for high precision in the shake correction, and which has a sufficiently reduced size.